Also available from Walmart [walmart.com] w/ free S&H on $ 35+. Well reviewed w/ 4.6 out of 5 stars by over 1700 Amazon customers.

About this item:
[LIST][*] 120 volt hardwire smoke alarm with photoelectric sensor and battery backup[*] Features convenient 9 volt battery backup, silence/test button, dust cover, 85 decibel alarm